Step 1:
\The function is
and point is
.
From gradient vector,
.
Consider
.
Apply partial derivative on each side with respect to
.

Substitute
in
.

Apply partial derivative on each side with respect to
.

Substitute
in
.

Then the gradient vector is
.
Step 2:
\The maximum rate of change of a function
at a point
occurs in the direction is
.
The magnitude of
is the maximum rate of change.
The maximum rate of change of a function
at a point
occurs in the direction is
.
The magnitude of
is
.
Solution :
\The maximum rate of change is 1.
\The direction of the maximum rate of change is
.